Anti-entrapment and anti-dead head function
AssigneesPentair Water Pool and Spa, Inc., Danfoss Low Power Drives
InventorsRobert W. Stiles, Jr., Lars Hoffmann Berthelsen, Peter Westermann-Rasmussen, Gert Kjaer, Florin Lungeanu
Life of this patent
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Abstract
Embodiments of the invention provide a system including a pump, a motor, and a controller. The controller establishes a baseline value of power consumption during a deadhead condition, increases a counter when a current value decreases below the baseline value, and determines a deadhead condition when the counter exceeds a limit. The controller also compares a current value to an immediately previous power consumption value to determine an entrapment condition indicated by a sudden decrease in power consumption.
Claims18
A pumping system for at least one aquatic application, the pumping system comprising:
- a pump;
- a motor coupled to the pump;
- and
- a controller in communication with the motor,
- the controller establishing a baseline value of power consumption of the motor during a deadhead condition,
- the controller determining a current value of power consumption of the motor,
- the controller increasing a counter when the current value decreases below the baseline value, and
- the controller determining a deadhead condition caused by a blockage downstream from the pump when the counter exceeds a limit.
A pumping system for at least one aquatic application, the pumping system comprising:
- a pump;
- a motor coupled to the pump;
- and
- a controller in communication with the motor,
- the controller comparing a current power consumption value of the motor to a substantially immediately previous power consumption value of the motor to determine a difference value,
- the controller shutting down the motor substantially immediately if the difference value indicates a sudden decrease in power consumption of the motor occurring during an entrapment condition caused by a blockage on a suction side of the pump,
- the controller performing a condition check to determine whether a speed of the motor has recently changed before shutting down the motor in order to avoid shutting down the motor due to torque ripple,
- wherein if the speed has recently changed, the controller calculates a power gradient baseline value based on the change in speed and corresponding oscillations in power consumption of the motor.
A pumping system for at least one aquatic application, the pumping system comprising:
- a pump;
- a motor coupled to the pump;
- and
- a controller in communication with the motor,
- the controller comparing a current power consumption value of the motor to a substantially immediately previous power consumption value of the motor to determine a difference value,
- the controller shutting down the motor substantially immediately if the difference value indicates a sudden decrease in power consumption of the motor occurring during an entrapment condition caused by a blockage on a suction side of the pump,
- the controller performing a condition check to determine whether a speed of the motor has recently changed before shutting down the motor in order to avoid shutting down the motor due to torque ripple,
- wherein if the speed has not recently changed, the controller calculates a power gradient baseline value based on a percentage of a present power consumption of the motor.
Dependencies are inferred from the claim text.